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ubi_assert(list_empty(&used)) in ubi_attach_fastmap

PATCH Nikhilesh Reddy 2 participants 2 messages May 22, 2015

Subsystems (3)
Memory technology devices (MTD) Arm STM32 Unsorted block images (UBI)
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Nikhilesh Reddy

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#0 lore raw

Hi

I am running kernel 3.10.

I recently saw an issue where ubi_assert(list_empty(&used)) in ubi_attach_fastmap always hits on a partition.

Searching this issue I found
http://git.infradead.org/linux-ubifs.git/commitdiff/a83832a7c8d023f446ec865926190951bd18a4b1?hp=36a87e44f642966442fd0d23f2ec536851e00236

drivers/mtd/ubi/fastmap.c +3 -1
index 600c4f9..9858bfb 100644 (file)
@@ -814,7 +814,9 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
        list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list)
                list_move_tail(&tmp_aeb->u.list, &ai->free);
 
-       ubi_assert(list_empty(&used));
+       list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list)
+               list_move_tail(&tmp_aeb->u.list, &ai->erase);
+
        ubi_assert(list_empty(&eba_orphans));
        ubi_assert(list_empty(&free));

Can you please give me a background on this patch. Is this safe to apply without any of patches in the list

http://lwn.net/Articles/618410/

Can this occur when trying to attach an empty partition? i.e. one that doesn't contain a UBI image.

Please let me know.
I would really appreciate any help that you can give me.

Signature · 6 lines
Thanks
Nikhilesh Reddy

Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
#1 lore raw

Hi!

Quoted 25 lines · Nikhilesh Reddy

Hi

I am running kernel 3.10.

I recently saw an issue where ubi_assert(list_empty(&used)) in ubi_attach_fastmap always hits on a partition.

Searching this issue I found
http://git.infradead.org/linux-ubifs.git/commitdiff/a83832a7c8d023f446ec865926190951bd18a4b1?hp=36a87e44f642966442fd0d23f2ec536851e00236

drivers/mtd/ubi/fastmap.c +3 -1
index 600c4f9..9858bfb 100644 (file)
@@ -814,7 +814,9 @@ static int ubi_attach_fastmap(struct ubi_device *ubi,
        list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list)
                list_move_tail(&tmp_aeb->u.list, &ai->free);
 
-       ubi_assert(list_empty(&used));
+       list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list)
+               list_move_tail(&tmp_aeb->u.list, &ai->erase);
+
        ubi_assert(list_empty(&eba_orphans));
        ubi_assert(list_empty(&free));
Quoted 4 lines

Can you please give me a background on this patch. Is this safe to apply without any of patches in the list

http://lwn.net/Articles/618410/

This is a tricky question but I tend to say "no". In my last fastmap series I've fixed a *lot* of issues. You need all fixes and they depend on each other.

My plan was to backport them to stable but as I'm horrible backlogged this plan hasn't materialized yet. ;-(

Quoted 2 lines

Can this occur when trying to attach an empty partition? i.e. one that doesn't contain a UBI image.

s/image/volume?

As the commit message says, it can happen in the powercut case. I don't think this is true for your case.
So, please backport all fixes to your custom kernel first.

Signature · 2 lines
Thanks,
//richard